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    SubjectRe: [PATCH] ARM: dts: imx6qdl: Specify IMX6QDL_CLK_IPG as "ipg" clock for SDMA
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    Am Sonntag, den 24.03.2019, 22:01 -0700 schrieb Andrey Smirnov:
    > Since 25aaa75df1e6 SDMA driver uses clock rates of "ipg" and "ahb"
    > clock to determine if it needs to configure the IP block as operating
    > at 1:1 or 1:2 clock ratio (ACR bit in SDMAARM_CONFIG). Specifying both
    > clocks as IMX6QDL_CLK_SDMA results in driver incorrectly thinking that
    > ratio is 1:1 which results in broken SDMA functionality(this at least
    > breaks RAVE SP serdev driver on RDU2). Fix the code to specify
    > IMX6QDL_CLK_IPG as "ipg" clock for SDMA, to the problem.

    As this is breaking DT backward compatibility, I think we need a
    blacklist in the driver for SOCs where the DT is known to be broken.

    But fixing the broken DT is still a good idea, so:

    Reviewed-by: Lucas Stach <l.stach@pengutronix.de>

    > Fixes: 25aaa75df1e6 ("dmaengine: imx-sdma: add clock ratio 1:1 check")
    > > Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
    > > Cc: Angus Ainslie (Purism) <angus@akkea.ca>
    > > Cc: Chris Healy <cphealy@gmail.com>
    > > Cc: Lucas Stach <l.stach@pengutronix.de>
    > > Cc: Fabio Estevam <fabio.estevam@nxp.com>
    > > Cc: Shawn Guo <shawnguo@kernel.org>
    > Cc: linux-arm-kernel@lists.infradead.org
    > Cc: linux-kernel@vger.kernel.org
    > ---
    >
    > This probably has been fixed already, so please ignore this patch if
    > that is the case.
    >
    > Thanks,
    > Andrey Smirnov
    >
    >  arch/arm/boot/dts/imx6qdl.dtsi | 2 +-
    >  1 file changed, 1 insertion(+), 1 deletion(-)
    >
    > diff --git a/arch/arm/boot/dts/imx6qdl.dtsi b/arch/arm/boot/dts/imx6qdl.dtsi
    > index 9f9aa6e7ed0e..354feba077b2 100644
    > --- a/arch/arm/boot/dts/imx6qdl.dtsi
    > +++ b/arch/arm/boot/dts/imx6qdl.dtsi
    > @@ -949,7 +949,7 @@
    > >   compatible = "fsl,imx6q-sdma", "fsl,imx35-sdma";
    > >   reg = <0x020ec000 0x4000>;
    > >   interrupts = <0 2 IRQ_TYPE_LEVEL_HIGH>;
    > > - clocks = <&clks IMX6QDL_CLK_SDMA>,
    > > + clocks = <&clks IMX6QDL_CLK_IPG>,
    > >    <&clks IMX6QDL_CLK_SDMA>;
    > >   clock-names = "ipg", "ahb";
    > >   #dma-cells = <3>;

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